Actually, it was the AE-1 that really boosted Canon. It was not a pro model, but sold in huge numbers (over 1 million), and locked in the Canon formula for success that they still use today. Produce cameras that are reliable, can be mass produced for a low cost, and flood the market with them. Nikon made better bodies, but they could not match the sales volumes or Canon's ability to have low prices and still make a high profit.
Canon still uses that formula, every penny spent to manufacture one has to be justified, they don't throw in frills unless they will payback in sales and profits.
Nikon got into trouble just a few years back, they were including questionable tech that was expensive to produce, cameras were difficult to assemble and repair, it cost them dearly because they could not match Canon's prices and still make a profit. I hope they have learned from that.
https://en.wikipedia.org/wiki/Canon_AE-1